Clean and quarter the strawberries. Pluck the fresh mint leaves from the stem and pour into a tea strainer. Let it steep for about an hour with the strawberry pieces, lemon juice, orange blossom water and preserving sugar.
Wash and peel the rhubarb and cut into 1 - 2 cm wide slices. Put a tablespoon of powdered sugar and the lemon zest over the cut rhubarb and let it steep as well.
Remove the tea bag with the strawberry mint after an hour and puree the strawberry mixture. Add the rhubarb, bring the whole mixture to the boil and bring to the boil for about 4 minutes.
Make a gel test. As soon as it succeeds, pour the jam into jars and close tightly.